School Choice or Best Systems_ What Improves Education_ - Margaret C. Wang [16]
When analyzing the change in achievement after a Michigan district is faced with charter school competition (at least 6 percent charter enrollment) between the years of 1992-93 and 1999-2000 on the Michigan Assessment of Educational Progress, Hoxby found: “Fourth-grade reading and math scores were, respectively, 1.21 and 1.11 scale points higher in schools that faced charter school competition after they began to face competition. Seventh-grade reading and math scores were, respectively, 1.37 and 0.96 scale points higher.”29 Hoxby points out that the traditional public schools faced with significant charter school competition in Michigan raised achievement relative to their own previous levels of performance and to that of other Michigan schools not subjected to competition from charter schools.
In Arizona, which is considered to have highly favorable legislation for charter schools, traditional public schools raised achievement when charter school competition reached critical thresholds. By 1999-2000, charter school enrollment reached 5.3 percent, the highest in any American state. Using methods similar to those used to study differences in achievement in Michigan, Hoxby found: “Achievement rose by 2.31 national percentile rank points on the fourth-grade reading exam, by 2.68 national percentile rank points on the fourth-grade math exam, and by 1.59 points on the seventh-grade math exam.”30 These gains are relative to the schools’ own initial performance and also to the gains made over the same period by Arizona schools that did not face charter school competition.
A separate study, by Booker, Gilpatric, Gronberg, and Jansen,31 used the rapidly growing number of charter schools in Texas to measure their effect on public school performance. By 2001-02, nearly 47,000 students were enrolled in 179 operating charter schools, up from 2,412 students in the first 16 charter schools that opened in 1996-97. Using eight-year panel data, the authors found results similar to Hoxby’s for districts “facing three or four percent charter penetration.”32 This study concluded:
Charter penetration is effective at raising performance levels of students remaining behind in traditional public schools especially when students are at schools that were performing below average in 1995-1996. Charter penetration, therefore, increases performance of students at traditional public schools, and differentially increases the performance of students at traditional public schools that were underperforming relative to other public schools.33
In North Carolina, Holmes, Desimone, and Rupp34 found that the steady increase of charter schools from 1996-97 to 2004-05 contributed to the rise in student achievement in traditional schools. By the end of the study period, there were 99 charters. (The charter legislation allowed for 100 charters.) Their analysis controlled for student demographic variables such as race, income, and competitive proximity of charters, and they concluded that despite the meager charter school enrollment of only 1 percent of North Carolina’s 1.25 million public school students,
[c]harter school competition raised test scores in [traditional] district schools, even though the students leaving district schools for the charters tended to have above average test scores. The gain was relatively large, roughly two to five times greater than the gain from decreasing the student-faculty ratio by 1, and more than one-half of the average achievement gain of 1.7 percent in 1999-2000.35
Offering contrary results, Paul Teske, Mark Schneider, Jack Buckley, and Sara Clark found competitive effects on traditional public schools lacking in Springfield and Worchester, Massachusetts; Jersey City and Trenton, New Jersey; and the District of Columbia. They concluded at that time that “charter competition has not induced large changes in district-wide operations, despite the fact that a significant number of students have left district schools for charter schools.”36
As they explained, state and district financial policies shielded